Assembly method for endoscope image pickup unit and endoscope

Abstract

In an assembly method for an endoscope image pickup unit, the endoscope image pickup unit includes a distal end portion main body portion including a front opening portion, a side opening portion, a rear opening portion and an arrangement space portion, a lens section including a distal end lens having an outer diameter that generally fits in the front opening portion, and an image pickup section that fits in the rear opening portion and includes an image pickup device arranged in an image forming position by a lens system such as the lens section. The assembly method includes steps for inserting the lens section into the arrangement space portion from the side opening portion, fitting the inserted lens section in the front opening portion, and fitting the image pickup section in the rear opening portion from a rear of the rear opening portion.

What is claimed is: 
     
       1. An assembly method for an endoscope image pickup unit including:
 a distal end portion main body portion including a front opening portion, a side opening portion, and a rear opening portion functioning as opening portions respectively opened to a front, a side, and a rear and an arrangement space portion that communicates with the three opening portions; 
 a lens section including a distal end lens having an outer diameter that generally fits in the front opening portion; and 
 an image pickup section that fits in the rear opening portion and includes an image pickup device arranged in an image forming position by the lens section or an image pickup device arranged in an image forming position by the lens section and a rear lens section arranged to be integrated with the image pickup device in a rear of the lens section, 
 the assembly method comprising: 
 an inserting step for inserting the lens section into the arrangement space portion from the side opening portion; 
 a fitting step for fitting the lens section, which is inserted into the arrangement space portion, in the front opening portion that communicates with the arrangement space portion; and 
 an image pickup section fitting step for fitting the image pickup section in the rear opening portion from a rear of the rear opening portion. 
 
     
     
       2. The assembly method for the endoscope image pickup unit according to  claim 1 , wherein
 the side opening portion is opened having an area equal to or larger than an area of projection to a side of the lens section to enable the lens section to be inserted from the side and opened having an area smaller than an area of projection to the side of the lens section and the image pickup section after assembly, and 
 the rear opening portion is opened having an inner diameter smaller than a maximum outer diameter of the lens section and substantially the same as an outer diameter of the image pickup section. 
 
     
     
       3. The assembly method for the endoscope image pickup unit according to  claim 2 , wherein
 the lens section includes an objective lens for front view for forming an image of an object on a front side of the front opening portion on an image pickup surface as a front-view object image and an objective lens for side view including a reflection surface for, in order to form an image of the object on a lateral side orthogonal to an optical axis direction of the objective lens for front view on the image pickup surface of the image pickup device as a side-view object image, reflecting the image twice, and 
 the assembly method includes, at least after the fitting step, an illumination member arranging step for inserting, from the side opening portion, a side-view illumination member that illuminates a side-view visual field of the objective lens for side view and arranging the side-view illumination member in the side opening portion. 
 
     
     
       4. The assembly method for the endoscope image pickup unit according to  claim 3 , wherein the assembly method further includes, after the image pickup section fitting step, a step for performing focusing to form the front-view object image and the side-view object image in a focus state on the image pickup surface of the image pickup device. 
     
     
       5. The assembly method for the endoscope image pickup unit according to  claim 4 , wherein, in the focusing step, the focusing is performed to respectively form, on the image pickup surface, the front-view object image in a circular region in the focus state and the side-view object image in a substantially annular region on an outer side of the circular region in the focus state. 
     
     
       6. The assembly method for the endoscope image pickup unit according to  claim 5 , wherein the endoscope image pickup unit mounted on an endoscope is assembled by the assembly method for the endoscope image pickup unit. 
     
     
       7. The assembly method for the endoscope image pickup unit according to  claim 3 , wherein the endoscope image pickup unit mounted on an endoscope is assembled by the assembly method for the endoscope image pickup unit. 
     
     
       8. The assembly method for the endoscope image pickup unit according to  claim 1 , wherein the endoscope image pickup unit mounted on an endoscope is assembled by the assembly method for the endoscope image pickup unit. 
     
     
       9. An endoscope comprising;
 an image pickup unit including:
 a distal end portion main body portion including a front opening portion, a side opening portion, and a rear opening portion functioning as opening portions respectively opened to a front, a side, and a rear and an arrangement space portion that communicates with the three opening portions; 
 a lens section including a distal end lens having an outer diameter that generally fits in the front opening portion; and 
 an image pickup section that fits in the rear opening portion and includes an image pickup device arranged in an image forming position by the lens section or an image pickup device arranged in an image forming position by the lens section and a rear lens section arranged to be integrated with the image pickup device in a rear of the lens section, wherein 
 
 the side opening portion is opened having an area equal to or larger than an area of projection to a side of the lens section to enable the lens section to be inserted from the side and opened having an area smaller than an area of projection to the side of the lens section and the image pickup section after assembly, and 
 the rear opening portion is opened having an inner diameter smaller than a maximum outer diameter of the lens section and substantially the same as an outer diameter of the image pickup section. 
 
     
     
       10. The endoscope according to  claim 9 , wherein
 the lens section includes an objective lens for front view for forming an image of an object on a front side of the front opening portion on an image pickup surface of the image pickup device as a front-view object image and an objective lens for side view including a reflection surface for, in order to form an image of the object on a lateral side orthogonal to an optical axis direction of the objective lens for front view on the image pickup surface of the image pickup device as a side-view object image, reflecting the image twice, and 
 a side-view illumination member that illuminates a side-view visual field of the objective lens for side view is further arranged adjacent to the lens section in the side opening portion. 
 
     
     
       11. The endoscope according to  claim 10 , wherein the image pickup unit is configured to form the front-view object image, which is generated using the objective lens for direct view, in a circular region on the image pickup surface of the image pickup device and form the side-view object image, which is formed using the objective lens for side view, in a substantially annular region on an outer side of the circular region on the image pickup surface of the image pickup device. 
     
     
       12. The endoscope according to  claim 11 , wherein the image pickup unit includes a first focus adjusting portion for forming the front-view object image in a focus state and a second focus adjusting portion for forming the side-view object image in the focus state. 
     
     
       13. The endoscope according to  claim 9 , wherein the image pickup unit includes a first focus adjusting portion for forming the front-view object image in a focus state and a second focus adjusting portion for further forming the side-view object image in the focus state before a first adjustment or after the first adjustment.